Bottom Line:
Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry.Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination.Despite its side effects, 80% of the patients would like to repeat the treatment.

Background: Masseter hypertrophy has been treated with botulinum toxin injections because of esthetic complaints especially in Asians.

Objectives: The goal of the present study was to evaluate the efficacy of abobotulin toxin use in masseter hipertrophy treatment in Brazilians.

Methods: Ten Brazilian female patients with masseter hypertrophy were subjected to injections of 90U of abobotulinum toxin A applied on each side respecting the safety zone stabilished in literature and were followed up for 24 weeks.

Results: When analyzing the coefficients between measures of middle and lower third of the face obtained from standardized photographs, an increase was observed, with statistical significance at 2 weeks (p=0.005) and 12 weeks (p=0.001). The progression of lower third reduction was 3.94%, 5.26%, 11.99%, and 5.47% (2, 4, 12, and 24 weeks respectively). All patients showed improvement in bruxism after treatment. Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry.

Conclusion: The use of abobotulinum toxin A for masseter hypertrophy is effective in Brazilians and reached its maximum effect of facial thinning at 12 weeks. Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination. Despite its side effects, 80% of the patients would like to repeat the treatment.

Mentions:
The coefficients between middle and lower thirds of the face at the different timepoints showed an increase compatible with thinning of the lower face at all time points,with statistical significance at 2 and 12 weeks as assessed by the Student's t test(Table 1). The same trend was observed forthe photographs in which patients ground their teeth. Graph 1 shows the pattern of facial thinning.

Mentions:
The coefficients between middle and lower thirds of the face at the different timepoints showed an increase compatible with thinning of the lower face at all time points,with statistical significance at 2 and 12 weeks as assessed by the Student's t test(Table 1). The same trend was observed forthe photographs in which patients ground their teeth. Graph 1 shows the pattern of facial thinning.

Bottom Line:
Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry.Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination.Despite its side effects, 80% of the patients would like to repeat the treatment.

Background: Masseter hypertrophy has been treated with botulinum toxin injections because of esthetic complaints especially in Asians.

Objectives: The goal of the present study was to evaluate the efficacy of abobotulin toxin use in masseter hipertrophy treatment in Brazilians.

Methods: Ten Brazilian female patients with masseter hypertrophy were subjected to injections of 90U of abobotulinum toxin A applied on each side respecting the safety zone stabilished in literature and were followed up for 24 weeks.

Results: When analyzing the coefficients between measures of middle and lower third of the face obtained from standardized photographs, an increase was observed, with statistical significance at 2 weeks (p=0.005) and 12 weeks (p=0.001). The progression of lower third reduction was 3.94%, 5.26%, 11.99%, and 5.47% (2, 4, 12, and 24 weeks respectively). All patients showed improvement in bruxism after treatment. Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry.

Conclusion: The use of abobotulinum toxin A for masseter hypertrophy is effective in Brazilians and reached its maximum effect of facial thinning at 12 weeks. Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination. Despite its side effects, 80% of the patients would like to repeat the treatment.